Grease burner



Jan, 9, 1968' E. 1.. KELLS ETAL GREASE BURNER 3 Sheets-Sheet 1 FiledApril 1965 Jan. 9, 1968 v E. L. KELLS ETAL 3, I

I 4 GREASE B RNER Filed April 9, 1965 v 5 Sheets-Sheet 2 Jan. 9, 1968 E.L. KELLS ETAL 7 3,362,359

Filed April 9, i965 GREASE BURNER 3 Sheets-Sheet 3 Zzward Z. fife/8 v $157 5 Wasfibzzrzz United States Patent Oiiice 3,362,359 Patented Jan. 9,1968 3,362,359 GREASE BURNER Edward L. Kells, Batavia, and Billy S.Washburn, West Chicago, Ill., assignors, by mesne assignments, toChicago Bridge dz Iron Company, Chicago, 11]., a corporation of IllinoisFiled Apr. 9, 1965, Ser. No. 446fi 13 (Ilaims. (Cl. 110-8) The presentinvention relates to a burner for disposing of greasy skimmings obtainedin the course of the disposal of sewage and the following disclosurethereof is offered for public dissemination upon the grant of a patenttherefor.

Sewage includes, depending upon the location, substantial amounts ofgrease. The disposal of this grease can be a diificult problem. This isdiscussed in greater detail in patent application No. 312,658, filedSept. 30, 1963, now abandoned, the disclosure of which is incorporatedherein by reference.

The principal object of the present invention is to provide a method of,and an apparatus for, burning waste grease which is relatively simpleand foolproof. Embodiments of the present invention can besatisfactorily operated by a relatively untrained employee, having nospecial knowledge or skills. There are no unusual maintenance problemssince the apparatus is relatively simple, with the operating partsbeing, in the main, standard items of manufacture. At the same time theburning does not create air pollution problems, which is becoming a moreand more important factor to the large communities.

Further objects and advantages will become apparent from the followingdescription taken in conjunction with the drawings, in which:

FIGURE 1 is an elevational view showing in vertical section a portion ofa building with an embodiment of the present invention installedtherein;

FIGURE 2 is a partial vertical section as viewed at line 22 of FIGURE 1;

FIGURE 3 is a horizontal-section as viewed at line 33 of FIGURE 2;

FIGURE 4 is a diagrammatic illustration of the burning action achievedthrough the use of the present invention;

FIGURE 5 is a partial vertical section of an alternate embodiment; and

FIGURE 6 is a partial vertical section of a second alternate embodiment.

Although the following disclosure offered for public dissemination isdetailed to ensure adequacy and aid understanding, this is not intendedto prejudice that purpose of a patent which is to cover each newinventive concept therein no matter how others may later disguise it byvariations in form or additions or further improvements. The claims atthe end hereof are intended as the chief aid toward this purpose; as itis these that meet the requirement of pointing out the parts,improvements or combinations in which the inventive concepts are found.

Furnace construction The furnace is annular in configuration beingformed by a cylindrical shell 10, a base 11 and a roof 12. Extendingupwardly from roof 12 is a stub chimney 13 which enters into the mainchimney 13'. The interior of the furnace has a suitable firebrick lining14 which, across the base, defines a hearth 15. Insulation (not shown)is provided between the metal shell and the lining 14. The metal shellalso defines an intake air plenum 16. Air is delivered to plenum 16under pressure through a pipe 17 from the discharge of a blower 18. Theintake for the blower is defined by a pipe 19.

A plurality of tubes 22 forming nozzles extend through roof 12 fromplenum 16. Through tubes 22, air jets are directed at hearth 15 at anangle to the surface of the hearth (FIGURES 2 and 4) all in the samerotational direction and with a component generally tangent to a circle23 on the hearth (FIGURE 3). Thus, for example, the air jet from one ofthe tubes 22 traverses a path 24 somewhat as depicted in FIGURES 2 and3, except that after being reflected from the hearth, the air goes up ina circular pattern about the central body of flame. This positioning ofthe air jets in the furnace is important to set up a burningconfiguration as discussed in connection with FIGURE 4. A plurality oftubes 25 extend through stub chimney 13 and are in communication withplenum 16. These tubes 25 likewise are positioned so as to impart awhirling motion to the air and other gases traversing stub chimney 13.As hereinafter described, stub chimney 13 thus forms an afterburner tocompletely consume the combustible material exiting through the stack.Additional air is introduced into the main chimney 13' through intakepipe 26.

Grease is introduced into the furnace through a distributor formed byconduit 27 having a discharge opening at 28. Conduit 27 has a verticalportion 27a and a horizontal portion 2712. Vertical portion 27a isconnected by a slip joint 29 to a feed pipe 30. It is journaled inbearings 31 and has a sprocket 32 afiixed therto. Sprocket 32 is drivenby a chain 33 connected to the output sprocket of a speed reducer 34which, in turn, is driven by a motor 35. Vertical portion 27a of theconduit extends through a sleeve 36 secured to the bottom of thefurnace. A cap 37 attached to portion 27a of the conduit preventsmaterial from falling down through between the sleeve and the conduit.

Conduit 27 is formed with a cut out 38 to facilitate cleaning of theconduit should any material become lodged therein. A removable section39 in one wall of the furnace forms an access door. By stopping theouter end of conduit 27 at a location adjacent removable section 39, itis possible to insert a rod through opening 38 in the conduit todislodge any accumulated material therein.

A rabble 42 is secured to conduit 27 by chains 43. The rabble dragsbehind the conduit and pushes accumulated ash toward a discharge pipe 44extending downwardly through the hearth 15. Sight glasses are mounted intubes 45 extending through the Wall of the furnace. Rabble 42, chains 43and conduit 27 are formed of stainless steel.

A blower 46 has its discharge tube 47 extending through the wall 10 ofthe furnace. A gas feed line 48 enters discharge tube 47 and has adischarge opening or gas burner 49 inside the discharge tube to preheatthe furnace to a suitable temperature for burning of the greasyskimmings. Electric ignition means (not shown) is provided for the gasburner.

Material feed The preparation of the greasy skimmings is very important.It is necessary that there not be large pockets of water incorporatedinto the skimmings. Any such large pockets of water reduce thetemperature in the furnace and may even cause a flameout. To preventthis the greasy skimmings are first decanted to eliminate the majorityof the water therefrom. The grease along with the remaining water isthen homogenized, blended or emulsified so as to thoroughly mix theremaining water with the grease. When so homogenized, the material hasthe appearance and texture of a dirty mayonnaise.

The apparatus for suitably conditioning and feeding the greasy skimmingsis illustrated in FIGURE 1. After decanting, the greasy skimmings arefed by a pump, not shown, through a pipe 50 to the intake of a hammermill 51 havingabout A" slots. The hammer mill grinds up any solidforeign material that may not have been previously eliminated. Inaddition, it does a rather effective job of emulsifying the grease andthe remaining water. From the hammer mill the skimmings are dischargedinto a holding tank 52. A propeller type blender in tank 52 is driven bya motor 53. The blender, by its agitation, maintains an emulsion in theholding tank. Should the blender not be operating, the materials in tank52 again will tend to separate with some decanting of the water therein.A valve 54 communicates with the bottom of tank 52 and is positionedabove a drain 55 so that any accumulated water in the bottom of the tankcan be drawn off.

Intake pipe 57 of a pump 58 communicates with tank 52 slightly above thebottom thereof. The discharge of pump 558 communicates with feed line30. It also communicates with a pipe 59 through a valve 60. Pipe 59, inturn, is connected to intake pipe 50. This permits a recirculation ofthe skimmings through hammer mill 51 to tank 52 when necessary ordesirable. Immediately adjacent the furnace, feed pipe 30 'has a T 61(FIGURE 2) to which is connected a valve 62 and a return line 63. Returnpipe 63 communicates with tank 52 adjacent the top thereof as best seenin FIGURE 1.

Operation To start the furnace, it is first preheated by the use of thegas burner 4% and blower 46. After it has been preheated to a suitabletemperature (e.g. 15 F.), the feeding of skimmings through conduit 27 iscommenced. After the temperature rises to about 1900 F., the gas isturned off but the blower 46 remains running so that no fumes back outthrough the blower. During the feeding of the skimmings the conduit isrotated, preferably at a speed of about 32 r.p.m. While the speed is notparticularly critical, relatively high speeds introduce bearingproblems. Also, it has been found that speeds too low to give a dosingfrequency of about 6 seconds, i.e. below about 10 r.p.m. in the case ofsingle outlets, do not produce such a distribution of the skimmings aswill create an even burning in the furnace. The furnace temperatureusually runs between about 2l002300 F., the principal variable being theamount of water in the skimmings. Automatic controls are provided torestart gas burner 49 if the temperature goes below 1900 F. and to shutdown the material feed if the temperature goes above about 2300 F.

The general pattern of the flame in the furnace is illustrated in FIGURE4. Except adjacent the hearth, the flame is confined to a central bodyof flame which is rotating very rapidly producing a vortex of flame. Theair jets from tubes 22 rebound from the hearth in such a fashion thatthey create an annulus of air rotating about the central body of flame.This has effects which are important to the operation of the furnace.The confining of the combustible gases to a central area results in avery high temperature being achieved. There is a complete destruction ofthe mercaptans, carbons, etc., which otherwise cause air pollutionproblems. Sufficient air surrounds and impinges upon this body of flameso that all of the combustible materials will burn. The injected airstirs and aerates the combustible vapors. It also has a protectivecooling effect on the hearth and distributor and prevents heavy clinkerformation. A further major advantage of the FIGURE 4 type of flameformation is that the walls of the furnace are washed with cool airrather than flame. Thus, the furnace linings have a much greater lifethan would be the case were they in direct contact with the hightemperature body of flame achieved to destroy the air pollutionmaterials.

Due to the rotation of the distributor 27 and the deposit of theskimmings in a ribbon 65 about the periphery of the hearth, the flamearises and burns from all sides of the hearth. In effect there is nowasted hearth space in the furnace. Of course, as the ribbon ofskimmings is heated on the hearth, it flows outwardly from the initialpoint at which it was deposited. The water is promptly boiled off andthe grease is vaporized. The grease should be introduced at a rate atwhich the burning rate is about 280,000 B.t.u.s per cubic foot offurnace volume per hour. The total volume of air introduced should be ata rate in excess of the stoichiometric amount (as related to the amountof combustible material) without being so excessive so as to cool thefurnace below about 1800 F. The fact that some of the air is introducedinto the afterburner assists in preventing over-cooling of the furnaceproper. While the furnace could be other than round in cross section,this would just result in unused corners which would fill up with ash,etc., resulting in a substantially round hearth. Furthermore, it wouldbe more difficult to obtain the whirling air and flame pattern of FIGURE4 with other than a round furnace.

The afterburner section defined by the short stack portion 13 isimportant to obtaining complete combustion. In this section additionalair is injected into and about the flame pattern to make sure thatcomplete combustion occurs. Additionally, the upwardly movement of theair jets cause them to aspirate gases out of the furnace thus reducingthe air pressure in the furnace proper. This results in an easing of thesealing problems about any openings and reduces the possibility ofgases, etc., escaping through openings in the furnace proper.

A substantial amount of the ash produced is very fine and will becarried up through the short stack 13. A wet scrubbing or electrostaticprecipitator means (not shown) should be provided to remove this fly ashbefore the combustion products are discharged into the atmosphere. Theremaining ash and slag is dragged to discharge conduit 44 by rabble 42.

When the furnace is to be shut down, the feed of material to conduit 27first is discontinued. When the furnace temperature drops to about 1900F., gas burner 49 is automatically ignited. This then supplies heat toclean up the hearth 15. Thereafter, motor 35 and burner 49 are shutdown.

Alternate forms of grease distribution FIGURE 5 illustrates an alternateform in which the hearth 70 is formed by a horizontal rotating tablehaving a metal bottom 71 with a firebrick cover thereover. Bottom 71 issupported on bearings 72 and is rotated by a shaft 73 secured thereto.An ash opening 74 is provided in the hearth and at one point in itscircle of revolution the ash opening is above a disposal pipe 75. Avalve plate 76 closes opening 74 except when it is above disposal pipe75. A feed conduit 77 extends through wall 10 of the furnace. As thehearth 70 rotates, a ribbon 73 of skimmings is deposited on the hearththrough the downwardly positioned discharge opening of conduit 77. Arabble 79 is pivotally mounted on a pin 80 and is positioned so that theash moving along hearth 70 will be pushed into open ing 74 FIGURE 6illustrates an embodiment similar to FIG- URE 2 except that thedistributor is in the form of a slinger which will throw the skimmingsby centrifugal force outwardly against wall 10 of the furnace where itslumps into a ribbon 81 at the base of Wall where the wall meets hearth15. The slinger includes a vertical rotating pipe 82 which substantiallycorresponds to vertical portion 27a of the distributor of FIGURE 2. Alower horizontal plate 83 is secured to pipe 82. A plurality of radialvanes 84 are fastened to plate 83 and an an upper plate 85 is attachedto the vanes. The greasy skimmings are ejected at the top of pipe 82 inthe space defined by the inner ends of the vanes 84. The skimmings flow.out through the space between the vanes and are ejected by centrifugalforce to fly toward the wall 10 of the furnace. Of course the slingermust be rotated at a sufficiently high speed so as to obtain thiscentrifugal distribution. As seen in a plan view, plates 83 and 85 wouldbe circular with vanes 84 evenly spaced about the axis of shaft 82 andextending radially outward from'the central space defined by their innerends.

We claim:

1. A burner for disposing of the grease obtained as skimmings from asewage disposal plant, said burner including: a furnace comprising agenerally cylindrical wall positioned with its cylindrical axis verticaland a hearth at the bottom of said wall; means to continuously deposit aribbon of grease about said hearth adjacent the cylindrical walls, saidmeans including a rotating distributor conduit having a discharge endadjacent said cylindrical walls from which end said ribbon is extrudedand means to rotate the conduit with respect to the furnace; and adevice including a plurality of nozzles extending into said furnace andmeans to introduce air into said nozzles under pressure.

2. A burner for disposing of the grease obtained as skimmings from asewage disposal plant, said burner including: annular furnace wallsformed about a vertical axis; a closed bottom for said walls andincluding a hearth member; an air jet device to direct air underpressure into said furnace in a plurality of streams, said streams beingdirected downwardly toward said hearth member at an angle to the hearthmember and with a component tangent to a circle on said hearth member; agrease introduction conduit member having a discharge openingimmediately above said hearth member from which opening said grease isextruded, said opening being positioned some distance from said axis;one of said members being rotatable about said axis with respect to theother; power means connected to said rotatable member to rotate thesame; and pump means connected to said conduit to introduce grease intothe conduit to be fed into said furnace through said opening; saidmembers being so arranged that the grease forms a ribbon on said hearthwhich ribbon is outside of said circle.

3. A grease burner as set forth in claim 2, wherein said hearth memberis rotatable.

4. A grease burner as set forth in claim 2, wherein said conduit memberis rotatable.

5. A grease burner as set forth in claim 4, wherein said conduit memberincludes an impeller rotated by said power means at sufiicient speed tocentrifugally impel said grease outwardly therefrom.

6. A grease burner as set forth in claim 4, wherein said conduit memberhas a downwardly discharge opening immediately above said hearth memberwith the conduit extending straight approximately from said axis to adownwardly turned portion above said opening, said condu'i having acleanout opening in said downwardly turned portion.

7. A grease burner including: annular furnace walls formed about avertical axis; a closed bottom for said walls and including a hearthmember, said hearth member having an ash opening extending downwardlytherethrough; an air jet device to direct air into said furnace in aplurality of streams, said streams being directed downwardly toward saidhearth member; a grease introduction conduit member having a dischargeopening immediately above said hearth member, said opening beingpositioned some distance from said axis; one of said members beingrotatable about said axis with respect to walls; power means connectedto said rotatable member to rotate the same; pump means connected tosaid conduit to introduce grease into the conduit to be fed into saidfurnace through said opening; and a rabble mounted on the conduit memberand adapted to drag on said hearth member.

8. A burner for disposing of the grease obtained as skimmings from asewage disposal plant, said burner including: annular furnace wallsfor-med about a vertical axis; a closed bottom adjoining said walls andincluding a hearth member; a chimney extending upwardly from said walls,the opening within said chimney being substantially smaller inhorizontal cross-section than is the opening within said walls; an airjet device to direct air into said furnace in a plurality of streams,said streams being directed downwardly toward said hearth member, saiddevice also introducing air directly into said chimney in a plurality ofjets; a grease introduction conduit member having a discharge openingimmediately above said hearth member from which opening said grease isextruded, said opening being positioned some distance from said axis;one of said members being rotatable about said axis with respect towalls; power means connected to said rotatable member to rotate thesame; and pump means connected to said conduit to introduce grease intothe conduit to be fed into said furnace through said opening.

9. A grease burner including: annular furnace walls formed about avertical axis; a closed bottom adjoining said walls and including ahearth member; a chimney extending upwardly from said walls, the openingwithin said chimney being substantially small in horizontal crosssectionthan is the opening within said walls; an air jet device to direct airinto said furnace in a plurality of streams, said streams being directeddownwardly toward said hearth member at an angle to the hearth memberand having a component tangent to a circle on said hearth member in agiven rotational direction, said device also introducing air directlyinto said chimney in a plurality of jets, said chimney jets beingdirected upwardly and in said rotational direction; a greaseintroduction conduit member having a discharge opening above said hearthmember and some distance from said axis; one of said members beingrotatable about said axis with respect to walls; power means connectedto said rotatable member to rotate the same; and pump means connected tosaid conduit to introduce grease into the conduit to be fed into saidfurnace through said opening.

10. A grease burner including: annular furnace walls formed about avertical axis; a closed bottom joining said walls and forming a hearth,said hearth having an ash disposal opening extending downwardlytherethrough, a chimney extending upwardly from said walls, the openingwithin said chimney being substantially smaller in horizontalcross-section than is the opening Within said walls; a greaseintroduction conduit extending upwardly through said bottom at saidaxis, outwardly to a point adjacent said walls and then downwardly andterminating in a discharge opening above said hearth, said conduit beingrotatable with respect to said bottom; means connected with the conduitexternally of said bottom to introduce grease under pressure into saidconduit; power means connected to said conduit to rotate said conduit; arabble connected to said conduit and adapted to drag on said hearth; andan air jet device to direct air into said furnace in a plurality ofstreams, said device also introducing air directly into said chimney ina plurality of jets, said chimney jets being directed upwardly and in arotational direction.

11. In the method of burning grease included in a mixture of grease andwater obtained from sewage in a furnace having a hearth, the improvementcomprising: separating the majority of the water from said grease;blending the remaining water and grease; continuously depositing saidgrease in a generally circular ribbon on said hearth; and blowing airfor combustion in a plurality of spaced jets directed downwardly towardsaid hearth at an angle thereto and having a component tangent to acircle concentric with and inside of said ribbon.

12. In the method of burning the thick grease obtained as skimmings froma sewage disposal plant in a furnace having a hearth and a chimney abouta vertical axis and extending upwardly from the furnace, the improvementcomprising: continuously depositing said grease about said hearth in agenerally circular ribbon about said axis; blowing combustion air underpressure in a plurality of spaced jets directed downwardly toward saidhearth at an angle thereto and in a given rotational direction aboutsaid axis whereby a vortex of flame rotating in said given directon iscreated in said furnace as said grease burns; and blowing air underpressure into said chimney in an upwardly direction and rotationallyabout said axis in said given direction.

13. In the method of burning the thick grease obtained as skinirningsfrom a sewage disposal plant in a furnace having a hearth, theimprovement comprising: continuously depositing said grease in agenerally circular ribbon about said hearth; and blowing combustion airunder pressure in a plurality of spaced jets directed toward said hearthat an angle thereto and having a component tangent to a circleconcentric with said ribbon, said ribbon of grease being depositedbetween said circle and the periphcry of the hearth.

References Cited UNITED STATES PATENTS Heath 15 8-4 Thornton 15 84Arnold 15828 Pecker 1108 McConechy 1 10-8 Peter 15 891 Breese 15 891 Reed 1 108 Hanley et al. 15 8-4 FREDERICK L. MATTESON, JR., PrimaryExaminer.

15 H. B. RAMEY, Assistant Examiner.

Patent No. 3,362,359

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION January 9, 1968Edward L. Kells et a1.

It is certified that error appears in the above identified patent andthat said Letters Patent are hereby corrected as show below:

Column 1, lines 18 and 19, cancel "now abandoned,";

line 20, after "reference." insert Patent 3,312,183 issued April 4, 1967on an application filed June 10, 1965 as a continuation of thatapplication. Column 6, line 19, "small" should read smaller Signed andsealed this 16th day of December 1969.

(SEAL) Attest:

Edward M. Fletcher, Jr.

Attesting Officer Commissioner of Patents WILLIAM E. SCHUYLER, JR.

1. A BURNER FOR DISPOSING OF THE GREASE OBTAINED AS SKIMMINGS FROM ASEWAGE DISPOSAL PLANT, SAID BURNER INCLUDING: A FURNACE COMPRISING AGENERALLY CYLINDRICAL WALL POSITIONED WITH ITS CYLINDRICAL AXIS VERTICALAND A HEARTH AT THE BOTTOM OF SAID WALL; MEANS TO CONTINUOUSLY DEPOSIT ARIBBON OF GREASE ABOUT SAID HEARTH ADJACENT THE CYLINDRICAL WALLS, SAIDMEANS INCLUDING A ROTATING DISTRIBUTOR CONDUIT HAVING A DISCHARGE ENDADJACENT SAID CYLINDRICAL